The invention relates to an arrangement for mounting and moving printers carriages in printing units.
In hard-copy printers, such as those being used for personal computers or text-printing devices, a dot-matrix print head is generally moved along a platen by means of a motor. The print head is attached to a printer carriage which in turn is supported by means of bushings on guide bars. The motor-driven line or toothed belt which serves as a traction mechanism is generally attached to a projection on the printer carriage or bushing.
During printing with printing units of this type, the printer carriage moves back and forth between two return points, and the bearings clearance in the bushings rocks the printer carriage at the return points during the carriage's change in direction. This rocking motion of the printer carriage produces additional noise as well as type misalignment.
This noise and misalignment is only acceptable in rudimentary printers.
There has been an attempt to compensate for these characteristics in high-quality printing units by hardening the bushings. However, this causes increased friction and greater wear. The use of high-precision backlash-free circulating ball sleeves to solve the problem involves considerable design and production costs.
One object of the invention is to develop a device for driving the aforesaid type of printer carriages such that the bearing clearance in the bearing elements of the printer carriage does not produce noise and type misalignment.